Second order coupling between excited atoms and surface polaritons

TL;DR

This paper introduces a second-order resonant two-photon process that enables atoms to couple to surface polaritons at finite temperature, expanding understanding of atom-surface interactions beyond the standard Casimir-Polder effect.

Contribution

The authors derive a new effective Hamiltonian describing resonant two-photon coupling between atoms and surface polaritons, revealing a novel energy exchange mechanism.

Findings

Resonant two-photon coupling enhances atom-surface interactions at finite temperature.

Second-order energy exchanges can be comparable to standard Casimir-Polder energies.

The model provides a new perspective on atom-surface dispersion interactions.

Abstract

Casimir-Polder interactions between an atom and a macroscopic body are typically regarded as due to the exchange of virtual photons. This is strictly true only at zero temperature. At finite temperature, real-photon exchange can provide a significant contribution to the overall dispersion interaction. Here we describe a new resonant two-photon process between an atom and a planar interface. We derive a second order effective Hamiltonian to explain how atoms can couple resonantly to the surface polariton modes of the dielectric medium. This leads to second-order energy exchanges which we compare with the standard nonresonant Casimir-Polder energy.